Method of making a loudspeaker



Sept. 29, 1964 Filed May 6, 1959 H. E. KLOSS METHOD OF MAKING A LOUDSPEAKER 2 Sheets-Sheet 1 INVENTOR.

HENRY E. KLOSS ATTORNEYS Sept. 29, 1964 Filed May 6. 1959 H. E. KLOSS METHOD OF MAKING A LOUDSPEAKER 2 Sheets-Sheet 2 INVENTOR.

HENRY E. KLOSS M QM ATTORN EYS United States Patent 3,150,441 METHQD (BF MAKING A LGUDSSPEAKER Henry E. Kloss, Cambridge, Mass, assignor, by mesne assignments, to KLH Research and Development Corp, Carnhridge, Mass a corporation of Delaware Filed May 6, 1359, Ser. No. 811,329 3 Claims. (Cl. 29-1555) This invention relates to loudspeakers and, more particularly, to a novel and improved assembly of a driving unit for a loudspeaker, a support member for the outer rim of a diaphragm for the loudspeaker, and a panel mounting the diaphragm support member.

A known construction for a loudspeaker comprises a magnetic driving unit for a voice coil associated with a conical diaphragm, a supporting ring-like member for supporting the outer larger end of the diaphragm with the supporting member being mechanically connected by a suitable frame or the like to the driving unit, and means on the support ring for mounting the speaker on a panel such as a particle board. The assembly of the driving unit to the support ring normally requires several operations involving the connection of the various parts by screws or other mechanical fastening means. Following the assembly of this subassembly of the speaker, an addi tional operation is required to secure or clamp the sup port ring to the panel in order to mount the speaker on the panel. The total manufacturing cost of this multistep assembly operation for assembling the speaker components as well as for assembling the speaker on a panel, for the most part, if not entirely, represents a labor cost and thus an appreciable portion of the over-all manufacturing cost of the resulting assembly. Consequently, a reduction in the number of operations, or a simplification of the operations required to assemble the driving unit and support ring subassembly as well as the assembly of the speaker on a panel will result in an appreciable reduction in the total labor time and expense for manufacturing the assembly and will provide a marked improvement in over-all manufacturing cost.

Accordingly, it is the primary object of this invention to provide a novel and improved construction of a diaphragm support ring and driving unit subassembly which will provide a rugged integrated structure lending itself to simplified and less expensive manufacturing procedures.

It is a further object of this invention to provide a novel and improved assembly of a diaphragm support ring and drive unit subassembly mounted on a panel wherein the assembly provides an integrated structure lending itself to easier and less expensive fabrication.

It is another object of this invention to provide a novel and improved method of assembling a diaphragm support ring and driving unit subassembly and also for assembling such a subassembly on a panel in a unitary operation so as to provide a marked reduction in assembly time and manufacturing cost of the loudspeaker.

It is still another object of this invention to provide novel and improved jig and die apparatus for practicing the novel and improved method of assembling a support ring and driving unit subassembly and also of assembling the subassembly on a panel simultaneously with the fabrication of the subassembly.

Other objects and advantages of the invention will be apparent from the detailed description hereinafter provided of preferred embodiments of the invention.

Briefly, in one aspect of this invention there is con templated the provision of a loudspeaker supporting panel having the usual opening for registry with a speaker cone or diaphragm. In accordance with the invention, the support ring for the outer end of the diaphragm is a plastic member formed integrally with the panel by molding the support ring about the panel opening so as to fabricate the support ring While simultaneously mounting it on the panel by the bonding of the material forming the ring to the bordering edge portion of the panel opening. Further, in accordance with the invention, a frame or bracket is rigidly connected to the panel by embedding one end of the frame within the material forming the support ring. The other end of the frame is embedded in a quantity of plastic material molded about a driving unit for the speaker so as to rigidly connect the other end of the frame to the driving unit and support the driving unit in centered spaced relation to the panel opening. In this manner, there is provided an integral rugged assembly of a panel and a diaphragm support ring and driving unit subassembly requiring no mechanical fastening means such as screws or the like and Wherein the assembly of the frame to the support ring takes place simultaneously with the fabrication of the support ring to provide a rugged integrated structure, thus facilitating fabrication of the final assembly as well as providing a marked reduction in manufacturing costs. A more detailed description of this aspect as well as other aspects of the invention may be had by reference to the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of a support ring and driving subassembly constructed in-accordance with this invention and mounted on a speaker supporting panel in the manner taught by this invention;

FIG. 2 is an elevational view, partly in cross section, of preferred die and jig apparatus for assembling the support ring, frame, and driving unit subassembly of a loudspeaker and mounting the same on a speaker panel all in a unitary operation; and

PEG. 3 is a top view of the jig and die apparatus of FIG. 2.

With reference to the drawings, and particularly FIG. 1, there is shown a diaphragm support ring and driving unit subassembly for a loudspeaker constructed in accordance with this invention and comprising a molded diaphragm support member 12 formed generally in an annulus or ring-like configuration and having a center opening for registry with the outer end of a generally conical diaphragm (not shown) for the loudspeaker. The ring 12 is cast onto a panel 11, preferably fabricated from what is often referred to as a particle board, with the panel 11 having an opening 13 for registry with the diaphragm of the speaker. The ring 12 is molded about the opening 13 and, in the preferred embodiment shown, is disposed within the opening 13 in bonded relation to the portion of the panel 11 defining the opening 13. Further, in the embodiment shown, the opposite sides of the ring 12 are flush with the opposite sides of the panel 11, and the support ring is provided with an inner rim or ledge 15 for supporting a surround or the like for a loudspeaker diaphragm. A magnetic driving unit 14 for the loudspeaker is disposed in generally centered axially spaced relation to the center opening in the ring 12 as well as the opening 13 in the panel. The driving unit may be of any suitable construction; however, in the specific embodiment shown, and as can be seen from FIG. 2, the driving unit comprises a cylindrical permanent magnet 16 polarized to provide opposite magnetic poles at the opposite ends respectively of the magnet. A pole plate 18 is engaged with one end of a magnet, and a post 26 is disposed in coaxial radially spaced relation within the magnet 16 and extends from the pole plate 18. As can be seen from FIG. 2, a quantity of plastic material, such as epoxy resin, is cast into the magnet 14 to bond the magnet, pole plate 18, and post 20 to provide an integral structure. A second pole plate 22 is engaged with the opposite end of the magnet and has a 3; central aperture into which projects the free end of the post 20. The bordering edge portion of the central aperture of the pole plate 2-2 is spaced radially outwardly of the post 20 to provide an annular air gap in which may be disposed a suitable driving coil (not shown) for the speaker diaphragm.

The driving unit is rigidly supported on the panel 11 by a frame 24 connected between the driving unit 14 and panel 11. In the preferred embodiment of FIG. 1, the frame 24 comprises a plurality of tubular metal struts 26 disposed angularly about the support ring and the opening 13 in the panel and extending angularly of and generally away from the Support ring and panel. In accordance with the invention, a cast supporting collar-like member 28 of a suitable material, such a epoxy resin, is molded about the driving unit 14 in bonded relation thereto, with one end of each of the struts 22-6 being embedded within the collar so as to rigidly connect the frame to the collar and thus to the driving unit 14. While the frame 24 could be cast from the same material forming the support ring, and thus as a single structure with the support ring, it is preferred, in most cases, to connect the other end of the frame or struts to the panel 11 by a quantity of cast plastic material, such as epoxy resin, which is cast onto the panel in bonded relation thereto, with the ends of the struts embedded therein. In the preferred embodiment of FIG. 1, the outer ends of the struts are received within apertures or pockets 3% separate from the opening 13 in the panel but preferably with the apertures 39 communicating with the opening 13. As will be later seen, the casting of the ring 12 as well as the embedding of the struts in the apertures 30 may be accomplished in a single step so that the struts are embedded in the material forming the ring 12 with the material in the apertures 30 generally forming ears or extensions 31 on the support ring. In order to enhance the bonding of the struts to the driving unit and support ring and/ or panel, it is preferred that each of the tubular metal struts be flattened at its inner and outer ends 32, 34 respectively, With the ends of the struts being turned outwardly so that each extends angularly from the adjoining remainder of the strut.

Thus, it will be seen that the support ring, frame, and panel provide a single integral structure. The resulting assembly will, as will be apparent from FIG. 1, provide a rugged structure free of the usual mechanical fastening means such as screws or the like. Also, while it will be apparent to those skilled in the art that the support ring need not be an integral part of the panel 11, but rather could be provided separately from the panel with additional means to attach the support ring to a panel, it is preferred to provide the integrated support. ring and panel structure in order to obviate the necessity for additional separate means for securing the support ring to the panel as well as to eliminate separate assembly operations and further, of course, to facilitate handling of the parts.

With particular reference to FIGS. 2 and 3, there will now be described a novel method for fabricating a driving unit and support ring subassembly, alone or in integral combination with a speaker panel, together with novel and improved apparatus for practicing such method of assembly. The preferred apparatus of this invention comprises a supporting member or table 3% on which is mounted die means for casting the molded plastic support ring 12. The die means include an inner die member 49 for forming the inner diameter of the support ring and a die member for forming the outer diameter of the support ring which is provided by the portion 41 of the panel 11 defining the opening 13 in the panel. It will be apparent to those skilled in the art that if it is not desired to mold the ring 12 and simultaneously bond the same to the panel 11, the die member for forming the outer diameter of the ring could be a suitable die memher having a surface corresponding generally to the opening defining portion 41 of the panel ill. A jig 42 supported on the table 38 supports the driving unit 14- in generally centered, axially spaced position relative to the panel opening 13. In order to provide accurate centering of the driving unit, the jig 42 is provided with a cylindrical member or sleeve 44- disposed coaxially of the panel opening 13 and extending into the air gap provided between the pole plate 22 and post 20 of the driving unit 14. The jig 42; also supports an additional die 46 which is generally a cup-shaped member surrounding the lower portion of the driving unit 14 so as to define a generally annular cavity around the driving unit. In a preferred embodiment of the invention, the die 46 is provided with a frusto-conical surface at the lower inner end thereof adapted to provide a frusto-conical seat 4-8 on the collar 23. This seat 43 is adapted to be used in supporting a spider or the like for carrying the voice coil of the speaker.

Additional jig means 56 are provided to position the frame 24 and maintain the frame in the desired position for assembly, with the inner end of the frame being disposed within the cavity of the die 46 and with the outer end of the frame being disposed within the cavity of the die means for forming the support ring. More specifically, the jig means 5% comprise a plurality of arms mounted on and extending outwardly from the jig 42 and terminating in spring clamps or other suitable means for engaging the struts 26 to support the same in the position shown in FIG. 2, wherein the outer flattened ends 34 of the struts are disposed within the apertures 30 of the panel and the struts extend through slots 51 in the die as with their inner flattened ends 32 engaged with the periphery of the driving unit. The strut receiving openings or slots 51 are preferably dimensioned so that the bodering edge portions thereof fit closely around the struts and pressure sensitive tape 52 is used to seal the upper portions of the slots. Further, as shown in FIG. 2, it is preferred that the ends 34 of the struts be spaced between the opposite faces of the panel 11 so as to be completely embedded by the material forming the support ring.

As apparent from FIGS. 2 and 3, it is preferred that the die means for forming the support ring and collar 23 be open at the top thereof in order to permit the collar and support rim to be gravity cast. From. the above, it is believed that it can be seen that with the various ele ments of the support ring, frame and driving unit subassembly and the panel it being arranged as shown in MG. 2, by the apparatus therein shown, a quantity of plastic material, preferably epoxy resin, may be poured into the open-topped support ring die so as to mold the support ring 12 While at the same time integrally bonding the support ring to the panel and bonding the frame to the panel and support ring. Further, a quantity of similar or the same material may be poured into the opentopped die 46 to mold the collar 28 and bond the frame to the driving unit to provide the rugged, integrated structure of FIG. 1. While it will be apparent that other apparatus could be used to practice the improved assembly method of this invention, and while obviously other methods could be utilized to provide the desired resulting structure, it is preferred to utilize the specific method and apparatus herein described in order to provide optimum achievement of simplicity as well as economy of manufacture.

Further, while the invention herein has been described in its various aspects in terms of certain specific and pre ferred embodiments, it will, of course, be apparent that various changes and alterations could be made in the structure, method, and apparatus specifically described without departing from the scope of this invention. Accordingly, the foregoing description and accompanying drawings are to be taken only in an illustrative sense and not as limiting the invention. Rather, it is intended that the invention shall be limited only by the appended claims, which shall include within their scope all structure which logically falls within the language of these claims. 7

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In the manufacture of a loudspeaker and integral panel wherein the loudspeaker frame supports the driving unit magnet elements in coaxial spaced relation to the panel opening in integral assembly with the panel with a diaphragm extending from the driving unit to the margin of the panel opening, the steps which comprise temporarily supporting the magnet elements in coaxial spaced relation to the panel opening, disposing a plurality of strut elements of the frame extending forwardly and radially outwardly from the driving unit magnet elements with the inner ends of the struts in predetermined fixed relation to the magnet elements and the outer ends of the struts within the margin of the panel opening, positioning a die member within the panel opening, and filling the space between panel and die member and around the outer ends of the strut elements of the frame outwardly of the die member with hardenable adhesive material to secure the frame to the panel and form a ring integral with the panel at the margin of the panel opening to receive and support the margin of the loudspeaker diaphragm.

2. In the manufacture of a loudspeaker and integral panel wherein the loudspeaker frame supports the driving unit magnet elements in coaxial spaced relation to the panel opening in integral assembly with the panel With a diaphragm extending from the driving unit to the margin of the panel opening, the steps which comprise temporarily supporting the magnet elements in coaxial spaced relation to the panel opening, disposing within supplementary panel openings the outer ends of a plurality of strut elements of the frame extending forwardly and radially outwardly from the driving unit magnet elements, disposing the inner ends of said struts in predetermined fixed relation to the magnet elements, positioning a die member within the panel opening, and filling the space between panel and die member and around the diaphragm extending from the driving unit to the margin of the panel opening, the steps which comprise temporarily supporting the magnet elements in coaxial relation to the panel opening, disposing a plurality of strut elements with their inner ends adjacent the magnet elements and the struts extending forwardly and radially outwardly from the magnet elements to the panel with the outer ends of the struts received within supplementary panel openings, positioning a die member within the panel opening, casting hardenable and adhesive material around the magnet elements and inner ends of the struts to form a unitary assembly of struts and magnet elements, and casting hardenable and adhesive material between panel and die member around the margin of the panel open ing and around the outer ends of the struts within the supplementary openings to form a ring integral with the panel at the margin of the panel opening to receive and support the margin of the diaphragm and to secure the struts of the loudspeaker frame to the panel.

References Cited in the file of this patent UNITED STATES PATENTS 1,898,031 Carter Feb. 21, 1933 1,941,476 Jensen Ian. 2, 1934 2,018,480 Apple Oct. 22, 1935 2,046,515 Jensen July 7, 1936 2,524,836 Russell Oct. 10, 1950 2,566,604 Eaves Sept. 4, 1951 2,666,980 Russell Jan. 26, 1954 2,915,812 Rettinger Dec. 8, 1959 

1. IN THE MANUFACTURE OF A LOUDSPEAKER AND INTEGRAL PANEL WHEREIN THE LOUDSPEAKER FRAME SUPPORTS THE DRIVING UNIT MAGNET ELEMENTS IN COAXIAL SPACED RELATION TO THE PANEL OPENING IN INTEGRAL ASSEMBLY WITH THE PANEL WITH A DIAPHRAGM EXTENDING FROM THE DRIVING UNIT TO THE MARGIN OF THE PANEL OPENING, THE STEPS WHICH COMPRISE TEMPORARILY SUPPORTING THE MAGNET ELEMENTS IN COAXIAL SPACED RELATION TO THE PANEL OPENING, DISPOSING A PLURALITY OF STRUT ELEMENTS OF THE FRAME EXTENDING FORWARDLY AND RADIALLY OUTWARDLY FROM THE DRIVING UNIT MAGNET ELEMENTS WITH THE INNER ENDS OF THE STRUTS IN PREDETERMINED FIXED RELATION TO THE MAGNET ELEMENTS AND THE OUTER ENDS OF THE STRUTS WITHIN THE MARGIN OF THE PANEL OPENING, POSITIONING A DIE MEMBER WITHIN THE PANEL OPENING, AND FILLING THE SPACE BETWEEN PANEL AND DIE MEMBER AND AROUND THE OUTER ENDS OF THE STRUT ELEMENTS OF THE FRAME OUTWARDLY OF THE DIE MEMBER WITH HARDENABLE ADHESIVE MATERIAL TO SECURE THE FRAME TO THE PANEL AND FORM A RING INTEGRAL WITH THE PANEL AT THE MARGIN OF THE PANEL OPENING TO RECEIVE AND SUPPORT THE MARGIN OF THE LOUDSPEAKER DIAPHRAGM. 